NASs aren't usually terribly difficult to impliment or maintain. Also depends on the kind of NAS it is - if it's a consumer level NAS than for the most part they're plug and play with relatively few options to have to set or be mindful of. If it's more of a storage server, like something running Windows [Storage] Server, there's a little more to it, but it's still not rocket science. Most of it depends on your level of knowledge and comfort around these sorts of things. Overall, not usually hard though.
With routers, it depends on the kind of router and the kind of networking setup the office requires. Most consumer and small-business grade routers are largely plug-and-play, but the higher end types (Cisco, Watchguard) can be more involved, and do not work right out of the box without various configurations being made. Again, depends a lot on the router and the kinds of things the router is needed for.
Any idea as to the kind of hardware you're being quoted? Any models?